Terrain Scale; Terrain Proximity - Garmin G500 Pilot's Manual

4.2

Terrain Scale

The Terrain Scale option in the Map page group selects whether the Terrain
Scale is shown on the Navigation Map. The Terrain scale will be located on the
right side of the display.
Color
Red Terrain is more than 100 ft above the aircraft.
Yellow Terrain is between 1000 ft below and 100 ft above the aircraft.
Black Terrain is more than 1000 ft below the aircraft.
4.3

Terrain Proximity

Garmin Terrain is a non-TSO-C151b-certified terrain awareness system
provided as a standard feature of GDU 620 to increase situational awareness and
help reduce controlled flight into terrain (CFIT). Terrain may be displayed on
the Map page group Navigation Map and Terrain pages.
Terrain Proximity uses information provided from the GPS receiver to
provide a horizontal position and altitude. GPS altitude is derived from satellite
measurements. GPS altitude is converted to a Mean Sea Level (MSL)-based
altitude (GPS-MSL altitude) and is used to determine Terrain alerts. GPS-MSL
altitude accuracy is affected by factors such as satellite geometry, but it is not
subject to variations in pressure and temperature that normally affect pressure
altitude devices. GPS-MSL altitude does not require local altimeter settings to
determine MSL altitude. Therefore, GPS altitude provides a highly accurate and
reliable MSL altitude source to calculate terrain and obstacle alerts.
Terrain Proximity utilizes terrain and obstacle databases that are referenced
to mean sea level (MSL). Using the GPS position and GPS-MSL altitude, Terrain
Proximity displays a 2-D picture of the surrounding terrain and obstacles relative
190-01102-02 Rev. E
Figure 4-1 Terrain Scale
Description
Table 4-2 Terrain Scale Color Codes
Garmin G500 Pilot's Guide
4-3